This invention relates to a solar fluid heating unit. More particularly, this invention relates to a solar water heater which comprises a molded one-piece manifold having a plurality of connections which is adapted to fit directly on a water pipe. In addition, the invention provides a method of assembling the entire distribution system of a solar water heater which is simple and efficient to conduct, and which can be easily accomplished in the field.
The attraction of using solar energy to heat water for swimming pools and hydrotherapy tubs, in addition to residential and commercial heating, is well known. Traditionally, solar water heaters have been made from metal, usually in the form of elongated metallic tubing which is painted black to aid heat absorption. These units have been generally heavy and rigid in nature, expensive to fabricate and maintain, and subject to damage by freezing. In more recent years, the metallic tubes have been replaced by mats of extruded elastomeric tubes which may be pre-colored black by including carbon black in the extrusion material. An example of such a product is described in Scholl, U.S. Pat. No. 3,648,768. Other patents disclosing systems similar to the one contemplated by the invention are MacCracken, U.S. Pat. No. 3,751,935, and Harter, U.S. Pat. No. 4,060,070. In the Scholl patent, the tubes are prepared for assembly by cutting away the webs and inserting the tubes onto the manifold. Various methods are then used to prevent the tubes from pulling out of the manifold including the use of flared screws, springs with tapered collars, and heat-shrink end caps. These methods all require the use of special tools and require special skills.
While the long tubular mats having a plurality of parallel tubes was a clear advance in the art, these tubes generally must be longitudinally separated from each adjacent tube, at least near the end portions, to attach the mat to a manifold. Typically, tubes in the mat are spaced by webbing in between the tubes, and the webbing is torn manually to loosen the ends of the tube so that they may be connected on-by-one to connecting members attached to a header. This method of assembly is somewhat time consuming, since it requires the separation of each tube, and frequently the shortening of alternate tubes by cutting the ends. In addition, assembly is usually performed in the field, where working conditions may provide a difficult environment for error-free connection of all of the tube members.
The present invention provides a simpler, less expensive, and faster method of constructing a flexible heat exchanger using an extruded tubular array. The assembly can easily be accomplished in the field without fear of failure. The system consists of a tubular header having radial holes bored therethrough, a one-piece molded manifold having a base portion which extends over the radial bore in the header and which has a plurality of radially extending aligned nipples protruding from the manifold base, and an attached tubular mat. The nipples are spaced to mate with the tubes of the extruded mat without separation of the tube ends. In other words, the mat may be forced over the nipples, thus joining all of the tubes on the mat with the manifold in one motion. Assembly of this system is accomplished first by applying adhesive to the base of the manifold and to the header, aligning the manifold over the bores in the header, and applying pressure. After the manifold is affixed to the header, an appropriate liquid adhesive is applied to the exterior surface of the nipples, and the entire end of the mat is aligned with the nipple array and is forced thereon, thereby sliding the tubes over the manifold connectors. The adhesive, while in a liquid state, acts as a lubricant to permit the tubes to slide over the nipples.
Accordingly, it is the object of the present invention to provide a system for assembling a flexible solar heat exchanger which is quickly and easily assembled, and for which the failure rate is virtually nil. It is another object of the invention to provide a solar heat exchange manifold in which all of the tubular connections can be made simultaneously. It is yet another object of the invention to provide a method of assembling a solar heat exchange system in the field which minimizes the number of assembly steps necessary to complete the assembly. These and other objects of the invention will be apparent from the following description of an embodiment thereof.